FDA is wrong on self-validation of COVID-19 tests

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While the world waits for vaccines and therapies, smart use of public health measures is critical for beating COVID-19. Testing is the essential tool for guiding public health.

FDA, America’s premier public health agency, contributed to the U.S.’s disastrous response by failing early in the outbreak to unleash the nation’s private and academic testing capabilities. It never made sense to wait for CDC to create a test because public health labs aren’t set up to run anything like the number of tests required. CDC’s fumbling of the test made things worse. The country has paid a heavy price for the six to eight weeks lost.

FDA is making another potentially disastrous decision on testing now, by allowing another kind of test, serologic antibody tests, on the market with no regulatory oversight.

The logic for permitting unregulated antibody tests, according to FDA, is that they are low risk because they aren’t being used to make medical decisions.

The tests, however, are being used to make life-and-death decisions. A false positive can lead people to believe they are immune to COVID-19 and therefore invincible, when in fact they may both be vulnerable to infection and capable of spreading the infection.

For example, the consequences could be devastating if a nurse in a care center for the elderly were to receive an incorrect result that she or he has recovered from COVID-19.

While serologic antibody tests could play an important role in reopening America, bad tests are far worse than no tests.

At the population level, inaccurate data about the presence or absence of the virus will lead public health officials and government leaders to make poor decisions.

FDA seems to believe that individuals or institutions have the ability to differentiate between good and bad antibody tests, or to validate the tests themselves.

That’s what FDA Commissioner Stephen Hahn suggested April 23 in an interview with BioCentury (see “FDA’s Hahn Denies Political Interference”).

“For end users to understand that validation, they need to look into the validation that a company's done, or do the validation themselves,” Hahn said.

That is an abdication of FDA’s responsibility. It is absurd to think the public can assess a manufacturer’s validation methods or that organizations can or should do their own validation.

No one would say that patients should assess the validation that a drug company has done on the purity of its products, or that they should do their own validation.

FDA has told companies to self-validate their antibody tests, and to label the fact that they haven’t been approved by FDA.

That’s insufficient. Validation of antibody tests is complex and requires access to large numbers of positive samples. FDA must provide clear requirements for validation before antibody tests are marketed.

The agency is working with the National Cancer Institute, CDC and academic labs to validate some antibody tests and to create standards.

This work needs to be completed before the market is flooded with tests of unknown validity.

FDA and CDC are losing the trust that is essential for them to accomplish their missions, and the looming debacle over antibody tests will only further erode confidence.

Already, public health experts are telling physicians and patients that they cannot rely on FDA to keep unreliable tests off the market.

The New York City Health Department issued a warning on April 22 against the use of serologic tests to diagnose acute or prior infection with SARS-CoV2, the virus that causes COVID-19. The tests “may produce false negative or false positive results, the consequences of which include providing patients incorrect guidance on preventive interventions like physical distancing or protective equipment.”

The warning noted that a serologic test cannot exclude infection in a patient with recent exposure to SARS-CoV2, and that cross-reactivity of antibodies to other common coronaviruses can confound results.

It isn’t enough for FDA to authorize antibody tests. It has to have the right standards. It isn’t clear that it has applied the correct standards for the handful of antibody tests that have been given Emergency Use Authorizations.

The Infectious Diseases Society of America issued a policy primer about antibody tests on April 22 that urges against their use for decision-making. It also makes an important point about the antibody tests FDA has authorized: even if they meet the standards FDA has set, the agency has set the bar so low that tests could be authorized even if they are likely to produce inaccurate results.

While serologic antibody tests could play an important role in reopening America, bad tests are far worse than no tests.

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